[hipwrshooter]

We just moved into our 8 yr old home two months ago. We discovered after purchase that our attic in the garage was not insulated and have arranged to have R-30 insulation blown in. I want to place a few pieces of 3/4" plywood trimmed to fit through access. My concern is the existing electrical lines which have been run over the 2'x10' rasters. I was considering notching the rater to recess the electrical. Is this advisable or should I place wood tabs on each side of cable that crosses the raster?

hipwrshooter

 

[Windows on Wash]

Do not notch your rafters (more likely trusses).

Why do you want to put down plywood?

Most garages will not be insulated by default. It's not required per code.

 

[hipwrshooter]

Attic electrical

Windows on Wash,
Thanks for the quick reply,
You are correct, I meant trusses not rafters. I need to place some plywood in the garage attic for additional storage space since we have downsized from our last home. When having an estimate done for the drop down ladder for access (I am a DAV and can't do myself) the contractor suggested placing insulation into the space. Texas is very hot in the summer and he stated that it would help cut down on the AC bill as it is an attached garage. Would running a few 1'x2' strips onto the trusses where I need to place plywood work just as well?

r,
hipwrshooter

 

[joecaption]

Plan heating or cooling the garage?
Is there a room above?
The right way would be to pull the wires and run then through the middle of the rafters so the whole floor could be used.
Second way is to run the wires along side of a 2 X 4.
They need to be protected from people stepping on them.

 

[AlphaPilot]

hip,

I have a few thoughts / comments. I see your concern with the wire. The easiest way to protect it? Just run 2x2 or 2x4 along one side, if not both sides of the wire that you're wanting to install your plywood over. Assuming your garage is attached, that probably means your attic in the garage shares the same attic as your house? If one is insulated (house) and the garage is not, I wouldn't think you'd gain much for an AC bill. My point here is, most modern day building requires your roof to vent. Your garage attic being uninsulated is just the same temperature of air that is passing through your insulated attic space 24/7. I'd like to know the science behind the cutting electric bills via insulated a space that will not be conditioned. (Now if you cool your garage, it is a different story.)

I would just be weery, and always wonder if they try to get more work with poor excuses. If you asked for a drop down access but got sold on insulation, that seems fishy.

 

[Ron6519]

The trusses might not be set up for storage. Check the engineering specs for the limits.

 

[Gary in WA]

Good points, of previous posts. Protect the wires; http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_38_par007.htm If the house TO garage WALLS are not insulated, I see the value. As mentioned, the attic/garage air is close to outside temps. Be sure to air seal/fire rated covering on the new stairs. Sell some stuff...

Gary